Heating pad



June 4, 1935. A. c. GILBERT HEATING PAD Filed Nov. 28, 1951 Patented June 4, 1935 PATENT OFFICE HEATING PAD Alfred 0. Gilbert, NortlrHaven, Conn, assignor to The A. 0. Gilbert Company, New Haven, Conn., a corporation of Maryland Application November 28, 1931, Serial No. 577,755

29 Claims.

My invention relates to a heating pad, and more especially to an electric resistance heating pad of the type which may be applied to the human body for therapeutic purposes or utilized in heating a bed, or the like.

Generally speaking, the invention relates to an electric heater in which a flexible, relatively flat envelope is provided in which the resistance elements are mounted, and one of the principal objects of the invention is to bring about a form of heater pad in which the heating elements may be readily assembled in the envelope.

A further object of the invention is to bring about a form of heating pad in which the envelope and heating units may be separately formed and assembledas unitary structures before the heating unit is assemb1ed within the envelope.

A still further object of the invention is to bring about a form of heating pad in which the heating elements are anchored within the protective envelope and held against movement therein.

To'these and other ends, the invention consists in the novel features and combinations of parts to be hereinafter described and claimed.

In' the drawing:

Fig. 1 is a plan view of a heating pad according to my invention;

Fig. 2 is a cross-sectional view along line 2-2 of Fig. 1, but on an enlarged scale;

Fig. 3 is a cross-sectional view along line 33 of Fig. 2, but on an enlarged scale;

Fig. 4 is a perspective of a modification, and

Fig. 5 is a view in cross-section of a constructional detail.

Referring to the drawing in which I have illustrated my invention by showing apreferred embodiment of the same, the reference numeral I0 indicates, in general, my improved heating pad which comprises an electric resistance heater, generally designated-by the reference numeral I I,

- and an envelope I2 of rubber or other suitable material.

The heating unit I I comprises a pair of spaced I sheets of suitable fabric I3 and I4, between which unitary structure or may be formed out of similar halves and 2I, vulcanized together at their edge portions. The envelope I9 is provided at one end with a hollow neck 22 and at its opposite end with an elongated projection 23, having an opening 24 of considerable width and providing for the introduction of the heating unit II into the interior of the envelope I9, the cord I8 of the heating element being first inserted through the opening 24 and then through neck 22, and the body of the heating'element being drawn into the envelope I9 after the cord I8. After the heating element has been placed within the envelope I9, the opposite faces 25 and 26 of the slit 24 may be joined together by a suitable cement or by the use of a strip or rubber impregnated tape, prior to which a number of threads 21, passing through the end 28 of resistance'heater I I are drawn outwardly through the opening 24, the ends of the threads being sealed between the opposite faces 25 and 26 to anchor the adjacent end of the resistance heater against movement, the cord I8 being he-d against movement in neck 22 by means of the annular rib or bead 29 formed within the opening in neck 22 and extending into the annular groove 30 in cord I8. The shape of the bead is such that it permits the ready insertion of the cord into the neck from the envelope but tends to oppose motion of the cord in the opposite direction. Thus, the bead 29 is provided at one side with agradually sloping surface 3| to permit the ready insertion of the cord through the neck 22, and an abruptly sloping surface 32 which, when the head is in the groove 30, opposes the movement of the cord I8 back into the envelope. 7

In Fig. 4 of the drawing I have shown a modification of the invention in which a piece of rubberized fabric or tape 33 is sewn or otherwise attached to the end of the heating element as at 34, a short piece of uncured rubber 35 being inserted between the lips 36 and 31, which is preferably cured under pressure by steam heat, thus sealing the lips together on the tape 33.

From the abo'vedescription ofthe invention it will be readily understood that the resistance heating element I I may be completely assembled in a unitary structure before being inserted within the envelope I9, the sealing of the open end of the latter completely closing the envelope and protecting the'resistance heater against the entrance of water or the like, the threads 21, or tape 33 as the case may be, which are sealed into the envelope, holding the adjacent end of the heater securely against movement while the opposite end is held against movement by the bead 29 in groove 30.

If repairs become necessary in the heating unit, the faces 25 and 26 may be separated by the insertion of a knife or the like and the opening 24% again formed whereupon the resistance heater may be withdrawn, repaired and sealed in the envelope i9 according to the above methods.

Preferably the opening or slit for the introduction of the heating element is located at that end of the envelope which is remote from the end having the hollow neck 22 to receive the conductor cord, andalong the sidesof the slit extend the opposing parallel lips which in conjunction form the elongated projection 23, previously referred to.

While I have shown and described a preferred embodiment of my invention, it will be understood that it is not to be limited to the details shown but is capable of modification and variation within the spirit of the invention and the scope of the appended claims.

What I claim is:

1. In a heating pad, a sealed envelope of plastic material, a flat relatively thin resistance heating element mounted loosely in the envelope, and means for attaching one of the edge portions of the heating element to the envelope comprising means attached to the heating element and embedded in the material forming the envelope and at one. end thereof.

2. In a heating pad, a sealed envelope of plastic material, a flat relatively thin resistance heating element mounted loosely in the envelope, and means for attaching an edge portion of the resistance heating element to the envelope comprising threads attached to the heating element and extending toward and being embedded in the material forming the envelope at one edge thereof.

3. In a heating pad, a hollow envelope sealed along substantially all of its edges to formsubstantially a one-piece structure, a resistance heating element assembled within the envelope, said envelope having a slit at one end thereof, means for sealing the slit in said envelope when the heating element is amembled within the envelope, and means for attaching an edge portion of the heating element to the envelope, said means comprising an element secured to the resistance heating element extending through and sealed in and with said slit by said sealing means.

5. In a heating pad, a hollow envelope sealed along substantially all of its edges to form substantially a one-piece structure, a resistance heating elementassembled within the envelope, said envelope having a slit at one end thereof, means for sealing the slit in said envelope when the heating element is assembled within the envelope, and means for attaching an edge portion of the heating element to the envelope, said last named means comprising threads attached to the heating element and extending into and sealed in and with the slit by said sealing means.

aooaeso 6. In a heating pad, an envelope of plasticma terial, a resistance heater in ,said envelope, said resistance heater comprising a sheet of fabric having resistance wires attached thereto, and

means for. attaching at least one edge portion of the fabric to the envelope, said last named means comprising threads passing through said fabric and embedded in the material of said envelope at an edge thereof.

7. In a heating pad, an envelope of vulcanizable material, a heating element assembled within said envelope, said envelope having a slit at one end thereof through which said element may pass,

said heatingelement comprising a sheet of fabric and an electric resistance heater attached thereto, means to seal the slit and means for securing one edge portion of the heating unit to the envelope comprising means on the heating unit extending into and sealed in and with said slit, said slit sealing means comprising a strip of vulcanizable material.

8. In a heating pad, an envelope of vulcanizable material, a heating element amembled within said envelope, said envelope having a slit at one end material, a heating element assembled within said envelope, said envelope having a slit at one end thereof through which said element may pas, said heating element comprising a sheet of, fabric and an electric resistance heater attached upon a surface thereof, means for sealing said slit, and means for securing at least one edge portion of said sheet of fabric to the envelope comprising a I piece of tape attached to said fabric extending into and sealed in and with said slit, said slit sealing means comprising a strip of vulcanizable material.

10. In a heating pad, an envelope of rubber, a resistance heating element assembled within the envelope, said envelope having a slit at one end thereof through which said element may pass, adhesive means for sealing the slit when the heating element is assembled within the envelope, and means for attaching an edge portion of the heating element to the envelope, said means comprising a piece of rubberized fabric attached to the resistance heating element and extending into said slit, said fabric being sealed'within said slit by said adhesive means.

11. In a heatingpad, a rubber envelope, a heating element assembled within said envelope, said envelope having a slit at one end thereof through which said element may pass, said heating element comprising a sheet of fabric and an electric resistance heater attached thereto, and a piece of rubberized fabric attached to an end of the sheet of fabric and extending into said slit, the slit end of the envelope being vulcanized to seal the slit and the rubberized fabric therein.

12. A heating pad comprising an outer covering in the form of a fiat envelope, said envelope having a hollow neck at one end and a sealed slit at the other end thereof, a flat resistance heating element within said outer covering, said heating element having terminals extending therefrom through and sealed in said hollow neck, the edge of 2,008,880 said heating element adjacent the sealed slit edge of said covering having elements secured thereto and extending therefrom into and sealed with said slit.

13. A heating pad comprising opposed sheets of material having their adjacent peripheral edges sealed together to form a flat and comparatively thin hollow envelope, and aresistance heating element secured to a flat sheet of material disposed within said hollow envelope, said sheet of material having the heating element thereon being secured to said envelope at one end by the sealing of heating element terminals in one edge of said envelope and at the other and opposite end by the sealing of an element secured to the adjacent edge of said sheet of material into the other and opposite edge of said envelope between the opposing sheets of material forming said envelope.

14. A heating pad comprising an outer covering of moisture-proof material in the form of a flat envelope, said envelope having a hollow neck at one end formed of the same material, said neck having an annular rib about its interior periphery, a heating element within said envelope, said heating element havinga terminal containing cord extending therefrom and through said neck, said neck being compressed closely about said cord and sealed thereto.

15. A heating pad comprising an outer covering of moisture-proof material in the form of a flat envelope, said envelope having a hollow neck at one end formed of the same material, said neck having anannular rib about its interior periphcry, a heating element within said envelope, said heating element having a terminal containing cord extending therefrom and through said neck, said neck being compressed closely about said cord and sealed thereto, said rib extending into the material of said cord to secure it to said neck against relative movement in respect thereto.

16. A heating pad comprising an outer covering of moisture-proof material in the form of a flat envelope, said envelope having a hollow neck at one end formed of the same material and having the material of its upper and lower portions extending beyond their meeting, point along the end thereof opposite said neck and extended laterally of said envelope substantially its entire width, a heating element within said en-* velope, said heating element having an extension piece disposed between said envelope extensions and sealed therebetween when they are sealed together, and a terminal containing-cord extending from said heating element through said neck and. sealed therein whereby said heating element is retained within said envelope free from its top and. bottom but secured against lateral movement by connection with said envelope at said neck and at the end opposite said neck.

17. A heating pad comprising an outer covering of moisture-proof material in the form of a flat envelope, said envelope having a hollow neck at one end formed of the same material and having the material of its upper and lower portions extending beyond their meeting point along the end thereofv opposite said neck and extended laterally of said envelope substantially its en- .tire width, a heating element within said envelope, said heating element having an extension piece disposed between said envelope extensions and sealed therebetween when they are sealed together, said neck having an annular rib about 1 its interior periphery, said heating element having a terminal containing cord extending therefrom and through said neck, said neck being compressed closely about said cord and sealed thereto whereby said heating element is retained within said envelope free from its top and bottom and side edges but secured against lateral movement by connection therewith at said neck and the end opposite said neck.

18. A heating pad comprising an outer covering of moisture-proof material in the form of a flat envelope, said envelope having a hollow neck at one end formed of the same material and having the material of its upper and lower portions extending beyond their meeting point along the end thereof opposite said neck and extended laterally of said envelope substantially its entire width, a heating element within said envelope, said heating element having an extension piece disposed between said envelope extensions and sealed therebetween when they are sealed together, said neck having an annular rib about cured against lateral movement by connection therewith at said neck and the end opposite said neck.

19. A heating pad comprising a hollow outer covering closely sealed along its entire peripheral edge, an electrical resistance heating unit loosely disposed within said covering, said heating unit having electrical terminals extending therefrom, said electrical terminals extending through and sealed with one edge of said. outer covering and said unit having supporting means secured thereto, said means extending into and sealed with another edge of said outer covering.

20. A heating pad comprising a hollow outer covering closely sealed along its entire peripheral edge, an electrical resistance heating unit loosely disposed within said covering, said heating unit having electrical terminals extending from one edge thereof, said electrical terminals extending through and sealed with an adjacent edge of said outer covering and said unit having supporting means secured to another and opposite edge thereof, said means extending into and sealed with an adjacent edge of said outer covering.

21. A heating pad comprising a hollow outer covering of material adapted to be flowed together at jointures thereof to seal the same, said covering being closely sealed along its entire peripheral edge, an electrical resistance heating unit loosely disposed within said covering, said heating unit having electrical terminals extending therefrom, said electrical terminals extending through and sealed with one edge of said outer covering and said unit having anchoring means secured thereto, said means extending into and sealed with another edge of said outer covering.

22. A heating pad comprising a hollow outer covering of material adapted to be flowed together at jointures thereof to seal the same, said covering being closely sealed along its entire peripheral edge, an electrical resistance heating unit loosely disposed withinsaid covering, said heating unit having electrical terminals extending from one edge thereof, said electrical terminals extending through and sealed with an adjacent edge of said outer covering and said unit an adjacent edge of said covering, said heating unit having electrical terminals extending from one edge thereof. said electrical terminals extending from and sealed with an adjacent edge of said outer covering.

24. In a heating pad, a flat flexible elastic outer envelope, a conductor cord extending into said envelope through one end thereof, a flat weblike heating element located within said envelope and connected with said conductor cord at one end of said element, and means for sealing the opposite end of said element within the marginal portion of said envelope.

25. In a heating pad, 2, flat flexible impervious outer envelope, and a flatweb-like heat transmitting member located within said envelope, said latter member also being flexible and held in assembled relation with respect to the envelope by being anchored to the envelope at opposite ends of said element.

26. In a heating pad, a flat flexible impervious said heat transmitting member being free of said envelope.

27. In a heating pad, 9. flat flexible elastic outer envelope having a slit along one margin, and a flat flexible web-like element within said envelope carrying flexible resistance heating means and having anchoring means extending into and sealed with said slit. Y

28. In a heating pad, a flat rubber envelope having a slit at one end, a flat flexible web-like element sealed at one margin in said envelope within and by said slit, flexible resistance wire carried by said element, and means at the opposite margin of said web-like element for holding it in place relatively to said envelope.

29. An electric heating pad comprising a flat flexible rubber envelope having a neck at one end, a web-like flexible element encased loosely in said envelope, 9. flexible resistance heating member carried by said web-like element and having terminals extending outwardly through said neck, and means at the end of the envelope opposite said terminals for anchoring and sealing said web-like element within the end portion of 

